Oilfield tubular spin-in and spin-out detection for making-up and breaking-out tubular strings

ABSTRACT

Spin-in and spin-out apparatus and methods are presented wherein an oilfield tubular spinner used in combination with a wrench detects the shouldering-up of tubulars during make-up and tubular thread disengagement during break-out. Sensors are employed to quantify measurables indicative of shouldering-up and thread disengagement, the measurables being used to shutdown spin-in and spin-out operations. Thresholds are employed to detect measurable values of interest. Timers may be employed to monitor and control the spin-in and spin-out operations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/293,742, filed Nov. 10, 2011, now allowed, which is adivisional application of U.S. patent application Ser. No. 11/852,519,filed Sep. 10, 2007, now U.S. Pat. No. 8,074,537, which claims priorityto U.S. Provisional Application No. 60/825,067, filed Sep. 8, 2006, nowexpired, the contents of each of which is hereby incorporated herein byexpress reference thereto.

FIELD

The present invention generally relates to oilfield tubular torquewrench spinners used in make up or breakout of wellbore tubular stringsand, in particular, to methods and apparatus for detecting tubularspin-in and spin-out completion.

BACKGROUND

Torque wrench tongs and spinners have been employed when making up orbreaking out tubular strings and, in particular, without limiting theinvention: drill pipe joints, drill collars, casing and the like in oilwell drilling operations. Such tubular strings are formed by threadedlyconnecting the tubulars in the string. In operation of a torque wrench,a spinner is utilized to initially rotate a first tubular relative to asecond tubular to thread the tubulars together. The spinner rotates thefirst tubular relative to the second tubular rather rapidly but at arelatively low torque and the tongs serve to finally tighten thetubulars together when making up a tubular string. Conversely, whenbreaking out a tubular string, the tongs initially break apart thethreaded connection between tubulars with the spinner subsequentlyunthreading the upper most tubular from the rest of the tubular stringat a relatively high speed and low torque.

SUMMARY

In accordance with a broad aspect of the present invention, there isprovided an oilfield tubular spinner for an oilfield tubular torquewrench, the oilfield tubular spinner comprising: a powered spin rollerincluding an axis of rotation; a spin motor operatively connected to,and configured to drive, the powered spin roller to rotate about itsaxis of rotation; and a shoulder-up system configured to detect ashoulder-up condition of a pair of tubulars being driven to threadedlyconnect by the powered spin roller and to initiate spin motor shutdownsubsequent to the detection of the shoulder-up condition.

In accordance with another broad aspect of the present invention, thereis provided a method for threadedly connecting an upper tubular and alower tubular using an oilfield tubular spinner and a torque wrench, themethod comprising: holding the lower tubular with the torque wrench;aligning the upper tubular with the lower tubular with their threadedintervals arranged for threaded connection therebetween; frictionallyengaging the upper tubular with the tubular spinner; operating ahydraulic motor of the tubular spinner to rotate the upper tubularrelative to the lower tubular; monitoring hydraulic fluid pressure ofthe hydraulic motor to detect a pressure condition of interest duringrotation of the upper tubular relative to the lower tubular; andshutting down the hydraulic motor after a pressure condition of interestis detected.

In accordance with a further broad aspect of the present invention,there is provided an oilfield tubular spinner for an oilfield tubulartorque wrench, the oilfield tubular spinner comprising: a powered spinroller including an axis of rotation; a spin motor operatively connectedto, and configured to drive, the powered spin roller to rotate about itsaxis of rotation; and a spin-out detection system configured to detect aspun-out condition of an upper tubular being driven by the powered spinroller to threadedly disconnect from a lower tubular and to initiatespin motor shutdown in response to the detection of the spun-outcondition.

In accordance with a further broad aspect of the present invention,there is provided a method for breaking out a threaded connectionbetween an upper tubular and a lower tubular using an oilfield tubularspinner and a torque wrench, the method comprising: holding the lowertubular with the torque wrench; frictionally engaging the upper tubularwith the tubular spinner; operating a motor of the tubular spinner torotate the upper tubular relative to the lower tubular; monitoring acondition of the upper tubular to detect a condition of interest duringrotation of the upper tubular relative to the lower tubular; andshutting down the motor after a condition of interest is detected.

It is to be understood that other aspects of the present invention willbecome readily apparent to those of ordinary skill in the art from thefollowing detailed description, wherein various embodiments of theinvention are shown and described by way of illustration. As will berealized, the invention is capable for other and different embodimentsand its several details are capable of modification in various otherrespects, all without departing from the spirit and scope of the presentinvention. Accordingly the drawings and detailed description are to beregarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings wherein like reference numerals indicatesimilar parts throughout the several views, several aspects of thepresent invention are illustrated by way of example, and not by way oflimitation, in detail in the figures, wherein:

FIG. 1 is a perspective view of a torque wrench and spinner mounted on amounting structure;

FIG. 2 is a top plan of a torque wrench and spinner according to oneembodiment of the invention;

FIG. 3 is a top plan view of a spinner assembly according to one aspectof the present invention;

FIG. 4 is a front elevation view of the spinner assembly of FIG. 3;

FIG. 5 is a left side elevation view of the spinner assembly of FIG. 3;

FIG. 6 is a perspective view of the spinner assembly of FIG. 3;

FIG. 7 is an enlarged view of a spinner roller assembly of the spinnerassembly of FIG. 3;

FIG. 8 is a schematic sectional view of a typical threaded connectionbetween drill pipe;

FIG. 9 is a graphical illustration of typical hydraulic system pressurevs. time during operation of a tubular spinner; and

FIG. 10 is a chart of a system according to the present invention.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various embodiments of thepresent invention and is not intended to represent the only embodimentscontemplated by the inventor. The detailed description includes specificdetails for the purpose of providing a comprehensive understanding ofthe present invention. However, it will be apparent to those of ordinaryskill in the art that the present invention may be practiced withoutthese specific details.

The present invention generally relates to tubular spinners used inmaking up or breaking apart oilfield tubular strings. Such strings aremade up of threadedly connected tubulars such as, for example, drillpipe joints, drill collars, casing and the like in oil well drillingoperations. The following description may refer to drill pipe and drillpipe joints, but it is to be understood that a torque wrench and tubularspinner may also be useful for the manipulation of other oilfieldtubulars.

A tubular spinner is often used with a torque wrench, also known as aniron rough neck. Commonly, a torque wrench includes tongs that grip androtate tubulars being handled and a tubular spinner includes rollersthat frictionally engage and rotate a tubular being handled. Inoperation of a torque wrench and tubular spinner, the tubular spinner isutilized to initially rotate an upper drill pipe when making up thedrill pipe, with the spinner rotating the pipe rapidly but at arelatively low torque and the tongs of the torque wrench serving tofinally tighten the drill pipe joints when making up a tubular string.Conversely, when breaking out a tubular string, the tongs initiallytorque the connection to “break” it and begin the unthreading process,with the tubular spinner subsequently unthreading the upper most tubularfrom the rest of the tubular string at a relatively high speed and lowtorque.

To facilitate understanding of tubular torque wrench tongs and spinners,reference may be made to FIGS. 1 and 2 for a brief description of oneembodiment thereof. One embodiment of a power actuated tubular torquewrench is generally designated by numeral 10 and illustrated inassociation with a drill rig floor 12, a supporting member including, inthis embodiment, an arm 16 which includes a laterally extending supportmember 18 for the wrench. The wrench is associated with a spinnergenerally designated by numeral 20, which is located above the wrenchfor spinning tubulars. Spinner 20 in this illustrated embodiment ismounted on the wrench and supported over floor 12 by the supportingmembers 16, 18.

While the invention is hereafter described utilizing hydraulicallyactuated power cylinders and a hydraulic circuit therefor, it will bereadily appreciated and understood by those of ordinary skill in the artthat any one or all of the power cylinders of this invention canalternately be pneumatic and a conventional pneumatic circuit may beused in conjunction therewith. Alternately, screw drives or otherdrivers may be used.

Wrench 10 includes drill pipe tongs including an upper tong 22 and alower tong 24 each of which may be substantially identical and whicheach include a body 26 with a generally U-shaped recess 28 in an edgethereof to receive oilfield tubulars to be handled thereby including forexample joints of drill pipe, drill collars, casing, wellbore liners andthe like. Recesses 28 are formed to accommodate tubulars extendinggenerally along an axis x through the recess. Axis x is substantiallyvertically oriented.

In the illustrated embodiment, tubulars 30 and 31 are positioned to beacted upon by the wrench tongs and the spinner. In operation, upper tong22 and spinner 20 generally act on an upper tubular 30 and lower tong 24generally acts on a lower tubular 31. Considering a normal oilfieldstring and its manipulation by a torque wrench, tubular 30 is the uppermost or last tubular and tubular 31 is the penultimate tubular of thestring. The tubulars 30, 31 are shown in phantom to facilitateillustration. With the upper tong 22 gripping an upper tubular and thelower tong gripping a lower tubular, tongs 22, 24 may be swiveledrelative to each other, which often includes holding one of the tongsstationary, while the other tong swivels relative thereto, to eithertorque up or break out a threaded connection between the tubulars.

The tongs may include various devices to permit tubulars to be gripped.For example, in one embodiment, a plurality of dies 34 having pipegripping teeth thereon are mounted in each recess 28. In the illustratedembodiment, dies 34 are mounted on die heads 38 that are moveable, as byhydraulics 39, pneumatics, screw drives, etc., toward and away from axisx. As such, dies 34 may be moved into a gripping position or pulled backfrom a gripping position, as desired. The die heads may be positioned inrecess 28, as shown, to act substantially diametrically opposite eachother to grip a tubular therebetween.

Each die head 38 may have an angular or curved surface on which its dies34 are mounted in spaced apart relation so that the dies are arrangedalong an arcuate path to generally follow the outer surface of a tubular30 to be gripped, which is also generally acuate. The spaced, angularpositioning may enable the dies 34 to engage spaced points on thecircumference of the drill pipe or tool joint.

The upper tong 22 may swivel in relation to the lower tong 24 to movethe tongs from a neutral position shown in FIG. 1 to one of the make upor break out torqueing positions. To permit the swiveling action, inthis embodiment, a double acting hydraulic piston and cylinder assembly96 may be provided adjacent the end of the tong bodies 26 remote fromthe die heads 38 which interconnects the upper and lower tongs 22 and 24so that by extending and retracting the torqueing piston and cylinderassembly 96 in timed relation to extension and retraction of the dieheads, the upper and lower tubulars 30 and 31 may be gripped and torquedin a manner to make-up or break apart a threaded connectiontherebetween.

Extension and retraction of the piston and cylinder assembly 96, in thisembodiment, causes the upper and lower tongs 22 and 24 to move towardand away from the torqueing position and into or through the neutralposition shown in FIG. 1. That is, with the upper tong 22 either inalignment with the lower tong 24 or the upper tong 22 moved into angularposition with respect to the lower tong 24, the tongs 22 and 24 aremoved in a swivelling manner and after each tong respectively grips byuse of dies one of a pair of tubulars positioned along axis x, thetubulars are rotated in opposite directions along axis x, for example,one in relation to the other.

When the tongs are properly aligned with oilfield tubulars 30, 31 to behandled, a threaded connection therebetween is positioned between thedies 34 of upper tong 22 and the dies of lower tong 24 with the tubularsextending generally along axis x. In that position, die heads 38 oflower tong 24 may be actuated to grip therebetween lower tubular 31.Then, depending upon whether the threaded connection is being made up orbroken apart, the torque piston and cylinder assembly 96 is extended orretracted. During the extension or retraction of the torque cylinder,the die heads 38 on the upper tong 22 will be in their retractedpositions so that the upper tong 22 can rotate in relation to the uppertubular 40. Thus, with the upper tong 22 released and the torque pistonand cylinder assembly 96 either extended or retracted to an initialposition depending upon whether the drill pipe is being made up orbroken out, the upper tong 22 may then be brought into grippingengagement with the upper tubular 30 by moving the die heads out toplace the dies carried thereon into gripping relation with the tubular.After this has occurred, both the upper tubular 30 and the lower tubular31 are securely gripped by the respective tongs. Then, the piston andcylinder assembly 96 is actuated for moving the upper and lower tongs 22and 24 pivotally in relation to each other thus torqueing the tubulars30 and 31 either in a clockwise manner or a counterclockwise mannerdepending upon whether the drill pipe is being made up or broken out.

In operation of the torque wrench, spinner 20 is utilized to quicklyrotate one of the pair of tubulars being handled while the other is heldagainst rotation by one of the tongs of the torque wrench. For example,when making up a drill string, spinner 20 is utilized to initiallyrotate drill pipe 30, which is the drill pipe being added to theremainder of the string, into threaded engagement with tubular 31, whichis held steady. When making up the drill string, the spinner rotates thepipe to be added rather rapidly but at a relatively low torque while theupper tong 22 is disengaged and the lower tong 24 grips, for example,bites into, tubular 31 to hold it steady. The tongs 22 and 24 serve tofinally tighten the threaded connection between drill pipe joints 30, 31when making up a drill pipe string. Conversely, when breaking out adrill pipe, the tongs 22 and 24 initially torque the connection at lowspeed and high torque to initiate an unthreading operation of theconnection with the spinner 20 subsequently frictionally engaging andunthreading the upper tubular 30 from the lower tubular 31 at arelatively high speed and low torque.

Making reference to the Figures, spinner 20 frictionally engages androtates a tubular being handled. Thus, a tubular spinner often has anoverall clamp configuration. For example in the illustrated embodiment,spinner 20 includes a pair of clamp arms 300, pivotally connected bypivot pins 302 to a frame for clamping about a tubular to be added tothe tubular string during make up, or about the upper most tubular,which is that tubular to be removed from the tubular string, duringbreak out. Of course, the invention is not limited to a clamp shapedspinner; a variety of other spinner configurations may be used.

Engagement between spinner clamp arms 300 and the tubular to be spun isthrough spinner rollers 310 and 312. Spinner rollers 310, 312 rotateabout an axis of rotation substantially parallel to axis x. Withoutlimiting the invention, the spinner rollers include one or more poweredrollers 312 and, optionally, idler rollers 310. While FIGS. 1 to 6 showpaired powered rollers 312 and idlers 310, the invention is not limitedthereto. For example, any number of powered rollers may be used. In oneembodiment, for example, four powered rollers are used without anyidlers.

The implementation shown in the Figures includes a powered roller 312and an idler 310 on each clamp arm 300. In the illustrated embodiment,the rollers are mounted on a clamp arm extension 304, which has someprovision for pivotal movement relative to its clamp arm 300, as throughpivot pin 308. In accordance with the implementation, the rollers 312and idlers 310 are moved from a neutral position towards axis x to aspinning position for engaging tubular 30 via clamping action of theclamp arms 300. Clamp arms 300 may be driven, for example, by ahydraulic or pneumatic cylinder 306 to open or close relative to axis x.The pivotal movement of clamp arm extensions 304 may allow the rollers312 and idlers 310 to engage and accommodate tubulars of variousdifferent diameters and to provide for a variance in grip pressure andpositioning the spinner 20 about a tubular 30. Each extension 304 may belimited in its pivotal motion relative to its arm to prevent theextension from moving out of a useful position during operation.Alternately or in addition, the two extensions 304 may be connected by alinkage to maintain their relative alignment during movement of clamparms 300 between the neutral and the spinning positions.

Powered rollers 312 are formed to frictionally engage a tubular to behandled. In one embodiment, rollers 312 are formed of durable materialssuch as steel. Rollers 312 may include surface treatments such as spiralgrooving, roughening, etc. to enhance engagement of the tubular. Duringspin-in and spin-out, spinning motion is imparted to the tubular 30 viarollers 312 as powered by motors 314. In particular, motors 314 driverollers 312 to rotate about their axis of rotation and in turn rollersengage and drive rotation of the tubular. In accordance with a pairedspin drive implementation, such as shown in FIGS. 1 to 6, or in amultiple spin drive implementation (not shown), each powered spin roller312 imparts spinning torque to the tubular 30, the spinning torquenecessary to spin tubular 30 about axis x being divided over themultiple motors 314 and rollers 312 associated therewith reducingindividual load and tear thereon. In one embodiment, motor redundancy isprovided should one of the motors 312 fail.

It could be said that tubular connection make-up may be divided intothree steps: spin-in, shouldering up, and tightening, and converselythat the tubular connection break-out may be divided into loosening andspin-out. Shouldering up is achieved when the entire tapered thread of apin end of the tubular being added to a tubular string is inserted inthe box end of the last tubular of the tubular string. With reference toFIG. 8, in some embodiments, the tubulars each include at one end ashoulder 413 adjacent the base of their pin threaded intervals 415 andat their opposite ends a threaded box end 417. The tubulars are formedsuch that the pin threaded interval 415 threads into the box end 417 ofa next tubular. Shouldering up is achieved when an end face 419 of thebox end butts against shoulder 413 of the pin end being threaded intothe box. It will be appreciated that the illustration of FIG. 8represents a standard oilfield drill pipe connection. Often, manyhundreds of identical type tubulars are used in series to form anoilfield string. Thus, during string handling the same connection typewill be acted upon repeatedly by the torque wrench.

The tightening and loosening of tubular connections may be performed asdescribed hereinabove using tongs 22 and 24 of the torque wrench,wherein relatively high torques are imparted to tubulars at relativelylow rotational speeds. In contrast, the spin-in and spin-out steps aredesirably performed at comparatively high rotational speeds by thespinner 20 while employing comparatively much reduced torque. Relativelyhigh spin-in and spin-out speeds are desired as tubular strings includelarge numbers of tubulars and as the minimization of make-up andbreak-out time overheads is desired.

It is desirable that the process of spinning-in a tubular be rapid toreduce the overall time for drill string handling. A person of ordinaryskill in the art would appreciate that high-speed spin-in imparts alarge angular momentum to the tubular 30. If the spinner roller(s) 312slip while being driven, the tubular being handled may be marred andboth the tubular and the spinner rollers may potentially be damaged.Thus, roller slipping should be avoided as much as possible.

Other variables require consideration when spinning-in andshouldering-up tubular 30. The thread on the pin end of tubular 30 istapered, as is the thread on the box end of tubular 31. The sametubulars 30 and 31 are used and reused in making-up and breaking-out anumber of tubular strings, which may result in cumulative wear of thetapered threads. As it may be appreciated, doping may be used to greasethe threads. The pipe dope has different viscosity under differentenvironmental conditions (i.e. temperature, humidity, etc.) anddepending on the type of pipe dope being used.

With reference to FIG. 9, in a tubular spinner applied torquesubstantially corresponds to the fluid pressure of the hydraulic systemdriving motors 314. Since system pressure may be monitored by a pressuretransducer and/or other means, the applied torque may conveniently bemonitored and understood by observing the hydraulic system pressureresponse. During a spin in operation hydraulic system pressure isoriginally at a starting level Pstart. When the driven rollers 312 arebrought into contact with a tubular and motors 314 are started up todrive rollers 312, the system pressure quickly jumps to an initialoperating pressure P1 and then gradually increases as the tubulars arethreaded together. When the threaded intervals of the pin end and boxapproach a shouldering condition, the force required to continue thethreading operation generally increases abruptly. As such, during thisportion of the spin-in operation, system pressure also can be seen toincrease abruptly, as shown in the region SP. When the tubulars shoulderup, the system pressure plateaus at a maximum pressure level Pmax. Incold weather operation of the same system, the system pressure willinitially jump to a higher initial operating level P1cold, primarily dueto increased viscosity in hydraulic system fluids and doping. However,the system pressure will gradually increase before undergoing an abruptincrease SPcold to eventually level off at maximum pressure when thetubulars being spun-in shoulder up. Maximum pressure during a coldoperation may generally be substantially similar to the maximum pressurePmax reached using that same system during warmer operating conditions.Cold weather operation may create a more linear increase over time fromthe initial operating pressure to a maximum pressure, wherein thepressure increase is less abrupt prior to shouldering up.

The maximum pressure Pmax of the tubular spinner hydraulic system can bedetermined such that an operator can establish a pressure threshold,Pthreshold, for the system. Pthreshold is substantially equal to Pmax.The operator can then actively or automatically control the system basedon the pressure threshold established for the system. In particular,since the pressure threshold offers an indication of a shouldered upcondition, an operator can monitor system pressure and use theestablished Pthreshold value to indicate a shouldered up condition.Pmax, and therefore the pressure threshold, may vary depending on theprofile of the tubulars being handled, for example, thread type, tooljoint design, etc. However, Pmax, and therefore Pthreshold, can bedetermined and recorded for a tubular spinner and for any of the varioustubulars to be handled, such that during operation measured pressure canbe compared against expected pressure conditions, such as the pressurethreshold. In addition, since tubular strings often include manyhundreds of similar connection types to be handled in direct succession,any established pressure conditions of interest can be used repeatedlyand systems can be set up based thereon.

With reference to FIG. 10, in order to control operation of a tubularspinner, in one embodiment, a pressure transducer 519 or other componentfor measuring hydraulic system pressure, may be positioned incommunication with the hydraulic drive system 520 for motors 314, forexample in or adjacent the pumping system 521, and a control system 523may be provided in monitoring communication C1 with pressure transducer519 and in control and monitoring communication C2 with pumping system521. Pressure transducer 519 and control system 523 may be used tomonitor operational hydraulic system pressure of the tubular spinner. Inone embodiment, for example, control system has stored thereto a valuefor Pthreshold and the pressure transducer and control system monitorfor Pthreshold in order to determine when shouldering up has beenaccomplished and, therefore, when the motors may be shut down. Forexample, in one embodiment, the control system may operate to shut thehydraulic system down when Pthreshold is reached, as sensed by pressuretransducer 519. Alternately, in another embodiment, the control systemmay activate or initiate other systems or steps when Pthreshold issensed, as discussed below.

A control system that monitors the roller motor's hydraulic systempressure may be useful in systems to prevent roller slipping. Forexample, rollers can slip when the tubular that they are rotatingshoulders up and can no longer be rotated. Thus, recalling thatPthreshold indicates that a tubular has shouldered up, it will beappreciated that shutting down the roller drive motors when Pthresholdis reached may prevent roller slipping.

However, additionally or alternately, further slip prevention optionsmay be employed. For example, in one embodiment, hydraulic systempressure may be monitored to detect a slip condition occurring prior toshouldering up. If the rollers begin to slip on the tubular, thehydraulic system pressure for the spinner may cease to increase and maybegin to fluctuate about a level lower than Pthreshold. If, for examplewith reference to FIGS. 9 and 10, the pressure sensed at pressuretransducer 519, as monitored by control system 523, levels off at apressure, shown by the line identified as SLIP, that is less thanPthreshold, the control system 523 may shut down the hydraulic system tothereby shut down motors 314. Control system 523 may include orcommunicate with a timer 525 for timing the various system functionssuch as motor operation and/or for monitoring the duration of pressureplateaus. If desired, control system 523 may include a communication C3to an operator interface 529. In a situation where slippage has beendetected, as by detecting a plateaued pressure below Pthresholdsubstantially maintained for a selected period of time, control system523 may shut down pumping system 521 to shut the motors down and/or maygenerate an error message at the operator interface to notify theoperator that a slippage problem has occurred and/or that the tubularspinner has been shut down.

In another embodiment, a shoulder-up time limit can be established forany particular type of tubular connection to be handled by a tubularspinner. The time required to spin-in and shoulder up a tubularconnection will be affected by the number of threads, flow rate of thehydraulic system, etc. and can be determined by testing. If the rollersbegin to slip, the threading in operation may be delayed or never becompleted such that the connection does not shoulder in the expectedconnection time. In such an embodiment, a timer, such as timer 525 canbe used to monitor the length of time from system start, when the motorsbegin to drive rollers 312 to spin the tubular, until a shoulder upcondition is detected, for example, when Pthreshold is reached. Ifthrough timer 525 and pressure sensing, as by use of transducer 519, itis determined that Pthreshold has not been reached in an expected timeframe, the system may determine that a problem has occurred and shutdown the motors. Again, an error message may be sent to an operatorinterface 529.

In accordance with an implementation of the invention, the pressuresensing and control systems may employ high-speed sense andcommunication electronics to effectively monitor and analyze the systempressure during operation.

As noted above, after a shouldering-up, the motors may be shut down.However, in accordance with another embodiment of the invention, aftershouldering-up, the tubular spinner may be permitted to operate for anadditional period to apply additional torque to the connection beingmade up. This additional time may be termed a “grunt” time, as shown inFIG. 9. For example, a “grunt” timer may be employed to run the spinnermotors 314 for a controlled period of time at high torque, to squeezeout the pipe dope. Thus, when Pthreshold is detected, indicatingshouldering up, the hydraulic pressure can be maintained to drive thedriven rollers 312 for a selected additional period, at the expirationof which the spin-in operation is shut down. A control system and atimer, such as, for example, control system 523 and timer 525, may beemployed to control the grunt time. The time period to which the timermay be set initially is dependent on environmental conditions and varieswith doping viscosity, but may be selected readily by observation of thetubular spinner operation.

The spin-out operation is started subsequent to the loosening of aconnection between tubulars 30 and 31. The spin rollers 312 may be usedto unthread enough of the tubular threads to allow disengagement of thetubulars 30 and 31. However, as soon as the pin and box threadsdisengage, the last thread of the upper tubular 30 drops down on thefirst thread of the lower tubular 31, called jumping. If the uppertubular 30 continues to be rotated after it is disengaged from the lowertubular 31 the last thread will repeatedly ride up the first thread ofthe lower tubular and drop down. During jumping, the threads may bedamaged to a lesser or greater extent by the impact therebetween. Thus,it may be useful to know when tubular 30 has been spun-out and thethreads have disengaged, to allow removal of the upper tubular 30 beforeit ever or repeatedly drops down on the tubular below it. On the otherhand, attempting to remove tubular 30 prior to thread disengagement mayresult in the tubulars 30 and 31 snagging and may possibly cause threaddamage.

In accordance with another embodiment of the invention, the tubularspinner may include a spin-out detection system to identify when a pairof tubulars has been fully or nearly spun-out so that the motors drivingthe rollers of the tubular spinner can be shut down. In one embodiment,for example, a system may be employed to monitor the number of tubularrevolutions (angular displacement) that the tubular undergoes during aspin-out operation and this can be compared against a known number oftubular revolutions required to disengage the threads of the tubularsbeing handled. For many oilfield tubulars, it may take between 2 to 21turns of one tubular relative to the other to disengage the threads.Depending on the tubular type being employed it may only require 3 to 4turns to disengage the threads, but in some situations it may takebetween 10 to 20 turns to disengage the threads. The number of turnsrequired to disengage a pair of tubulars, is readily determinable andmay already be publicly known for some tubular types. In such a system,an encoder may be employed to count the number of tubular revolutionsbeing driven by the tubular spinner.

In accordance with an implementation of this embodiment of theinvention, an encoder may be employed to sense number of turns of acomponent of the tubular spinner, such as the motor 314, or rollers 310,312, for example rotations of the motor shaft, motor gears, rollershaft, etc. This count can be used to determine the number of times thetubular 30 is rotated about its axis. As will be appreciated, such acorrelation may be made based on the diameter of the roller and thediameter of the pipe being rotated. During operation, an operator mayinput a pipe diameter being handled to a control system such that thetubular spinner may be automatically controlled to stop after theselected number of tubular rotations for that pipe diameter. If desired,a detector may be employed on the tubular spinner, for example, todetect the space between the rollers to automatically determine the pipediameter of the pipe being handled and therefore, the ratio of a rollerrotation to a pipe rotation.

It is to be noted, however, that in practice the spin-out operation maystart with the driven rollers 312 skipping over the surface of thetubular being handled which does not preserve the ratio of motor 314revolutions to tubular 30 revolutions thus introducing errors in thecounting of the turns; the discrepancy being non-determinable. Also, ifthe tubular 30 being unthreaded is not clean, this may also introduceproblems in sensing/measuring tubular rotation. These possible errorsmust be considered in the use of a tubular rotation count to detect aspun-out condition.

In accordance with another implementation of the embodiment of theinvention, an accelerometer may be employed to detect acceleration orjerk (changes in acceleration) during thread jumps. An accelerometer maybe employed with high-speed feedback electronics to monitor theaccelerometer output. The accelerometer may be installed adjacent thetubular being handled, such as a portion of the spinner frame forexample on arm 300 or extensions 304 to monitor vertical tubularaccelerations and, in particular, the G forces generated by the tubular.The accelerometer may generate a signal for handling by a controlsystem, for example to alert an operator or for processing for automatedoperation. In the high vibration environment of well bore drilling; theaccelerometer may be affected by false triggering. Also, at least onethread jump must be incurred for the accelerometer to trigger and athread jump occurs in such a short period that normal electronicmonitoring rates sometimes can miss one or more thread jump events.

In accordance with a further implementation of the embodiment of theinvention, a linear transducer may be employed to detect linearseparation between the upper and lower tubulars 30 and 31, reverselinear displacement in the separation indicating thread jump. The lineartransducer may be installed on a stationary structure, such as a portionof the spinner or torque wrench frame, adjacent the tubular beinghandled. The linear transducer may be installed between a stationarypoint and the tubular or the rollers, which tend to move vertically withthe tubular, to monitor vertical displacements of the tubular vs. time.Again, with the thread jump being very sudden and occurring during ashort duration of time, a highly sensitive linear transducer andhigh-speed feedback electronics may be employed to read the lineartransducer output and feed that to a control system. In the highvibration environment of well bore drilling; the linear transducer maybe affected by false triggering. Also, at least one thread jump must beincurred for the linear transducer to trigger.

In accordance with yet another implementation of the embodiment of theinvention, a spin-out timer may be employed based on spinner motor 314operations to spin-out the tubular 30 before reassessing tubulardisengagement. The spin-out timer, which may for example be a timercomponent 525 of a control system 523, is started as the spin-outoperation is started (i.e. when the motors start rotating) and giventubular parameters such as, but not limited to: the thread taper, threadpitch and spin-out speed, may typically be set at 3 to 5 sec roughlycorresponding to 3 to 4 revolutions of the tubular 30. After theallocated spin-out time elapses, as monitored by the timer, the motorsare shut down to stop the spin-out process. If the tubulars 30 and 31have not disengaged within the period allowed by the timer, tubular 30may be spun again for another, possibly shorter, period of time. Anestablished time for disconnection for any particular tubular connectiontype in any particular tubular spinner may be stored to control systemand the breaking out process can be controlled by the control systememploying its timer component.

In the above it is understood that employing various of these systems,may require a comparator for comparing measured values to theestablished values of interest. It is further understood that employinga values of interest may require the storage of the values, possibly inmemory storage. This is true for example in some systems employingpressure thresholds, system pressures, operational times, etc.

It is understood that the various aspects of the invention and thatvarious elements of the implementation described may be employed alone,severally and in various combinations to improve spin-in and spin-outdetection in making-up and breaking-out tubular strings, withoutlimiting the invention.

The previous description of the disclosed embodiments is provided toenable any person of ordinary skill in the art to make or use thepresent invention. Various modifications to those embodiments will bereadily apparent to those of ordinary skill in the art, and the genericprinciples defined herein may be applied to other embodiments withoutdeparting from the spirit or scope of the invention. Thus, the presentinvention is not intended to be limited to the embodiments shown herein,but is to be accorded the full scope consistent with the claims, whereinreference to an element in the singular, such as by use of the article“a” or “an” is not intended to mean “one and only one” unlessspecifically so stated, but rather “one or more”. All structural andfunctional equivalents to the elements of the various embodimentsdescribed throughout the disclosure that are known or later come to beknown to those of ordinary skill in the art are intended to beencompassed by the elements of the claims. Moreover, nothing disclosedherein is intended to be dedicated to the public regardless of whethersuch disclosure is explicitly recited in the claims. No claim element isto be construed under the provisions of 35 USC 112, sixth paragraph,unless the element is expressly recited using the phrase “means for” or“step for”.

What is claimed is:
 1. A method for making up a threaded connectionbetween an upper tubular and a lower tubular using an oilfield tubularspinner and a torque wrench, the method comprising: holding the lowertubular with the torque wrench; frictionally engaging the upper tubularwith the tubular spinner; operating a motor of the tubular spinner tospin-in and shoulder-up a tubular connection between the upper tubularand the lower tubular; establishing a threshold hydraulic systempressure that indicates a shouldered-up condition; monitoring, with adetection system, a hydraulic system pressure of the motor duringspin-in and shoulder-up; detecting that the threshold hydraulic systempressure is reached; and operating the motor of the tubular spinner fora period of time at high torque after the threshold hydraulic pressureis reached.
 2. The method of claim 1, wherein monitoring comprisescomparing a measured hydraulic system pressure to the thresholdhydraulic system pressure.
 3. The method of claim 1, wherein thehydraulic system pressure is monitored to detect a slip condition priorto shouldering-up.
 4. The method of claim 3, which further comprisesshutting down the motor after the detection system determines that ahydraulic system pressure below the threshold hydraulic system pressurehas been maintained for a selected period of time, indicating that aslip condition has occurred.
 5. The method of claim 1, which furthercomprises monitoring a period of time for operation of the motorsuitable for substantially establishing a shouldered-up condition. 6.The method of claim 1, which further comprises tightening the tubularconnection with the torque wrench after spin-in and shoulder-up.
 7. Themethod of claim 1, wherein the motor is selected to comprise a hydraulicsystem driving motor.
 8. The method of claim 1, wherein the torquewrench is selected to comprise tongs and the tubular spinner is selectedto comprise a plurality of rollers.
 9. The method of claim 8, whereinthe motor comprises a plurality of spin motors associated with therollers to reduce a load on each of the spin motors.
 10. The method ofclaim 1, wherein the torque wrench is adapted to grip and rotate thelower tubular and the tubular spinner is selected to frictionally engageand rotate the upper tubular.
 11. The method of claim 1, wherein thehydraulic system pressure jumps to an initial operating pressure whenthe tubular spinner is engaged, and then gradually increases as theupper and lower tubulars are threaded together.
 12. The method of claim1, wherein the threshold hydraulic system pressure comprises a plateauin the hydraulic system pressure.